Journal of Wireless Networking and Communications 2012, 2(5): 117-125 DOI: 10.5923/j.jwnc.20120205.06 Parametric Study of UWB Biconical Antenna for Wide-band Applications Rakesh Kumar Yadav1,*, Sushrut Das 1, R. L. Yadava2 1Department of Electronics Engineering, Indian School of Mines (ISM), Dhanbad, 826004, India 2Department of ECE, Galgotias College of Engineering & Technology, Gr. Noida, 201306, India Abstract This paper presents Ansoft HFSS based parametric analysis and design of UWB b icone antenna. The design frequency of proposed antenna is 2.4 GHz. This antenna covers the 1.3 ~ 17.5 GHz frequency band with Return loss less than -10 d B. The bandwidth has been achieved by making a simple and easy modification in the design parameter of the bicone antenna. The voltage standing wave ratio (VSWR) less than 2 within the frequency range of 1.3 GHz ~ 17.5 GHz of this antenna is noticed. This antenna can be used in S (2 GHz to 4 GHz), C (4 GHz to 8 GHz), ext. C (3.4 GHz to 6.725 GHz) and X (8 GHz to 12 GHz) band frequencies and all three frequency band of industrial, scientific and medical (ISM ), which are reserved internationally for the use of radio frequency (RF) energy for purposes other than communications. Exa mp les of applications in these bands include radio-frequency process heating, microwave ovens, and medical diathermy machines. Ke ywo rds Radiation Pattern, Biconical Antenna, Ult ra Wide Band, VSWR and Transverse Electromagnetic (TEM ). rich scattering environments by the use of multiple antennas) 1. Introduction with UWB technology is more and more studied. It seems to be a very potential approach for enhancing Wireless communication is the fastest growing field of capacity, increasing range, raising link reliability and communication technology which has captured the attention improving interference cancellation. There are two criteria of social life in the present scenario. For the successful available to identify an antenna to be considered as an Ultra implementation of any wireless communication system, the Ta b l e 1 . Frequency band allocat ions antenna technology plays one of the important roles. A proper design of the antennas can reduce the system Sy st em Descript io n Frequency Band requirements and improve the overall system performance. DVB-H Digital Video Broadcasting 470-890 MHz An overview of the frequency band allocated for modern Global System for mobile GSM-900 880-960 MHz wireless communication standards are summarized in Table communicat ion 1. Global Position Systems 1227.60 MHz GP S Ultra Wideband (UWB) is an emerging technology for 1575.42 MHz Digit al Communicat ion 1710-1795 MHz future short-range wireless communications with high data DCS-1800 rates as well as radar and geolocation. A landmark patent in Sy st em P ersonal Handy-Phone UWB communications was submitted by Ross in 1973. PHS 1905-1920 MHz Sy st em s However, it was in 1989 that the term “Ultra Wideband” Personal Communicat ion 1850-1990 MHz PCS-1900 appeared in a publication of department of defence in the Sy st em United States (U.S.) and the first patent with the exact Universal Mobile 1920-2170 MHz UMT S Telecommunications phrase “UWB antenna” was filed on behalf of Hughes in 1993. To guarantee the coexistence of UWB with other Sy st em s Wi-Br o Wireless Broadband 2300-2390 MHz communication standards, the authorized transmitted power Radio Frequency RFID 30 – 2400 MHz is always very low which limits the development of UWB Ident ificat ion Systems communication systems with very high data rates and/or the 2400-2484 MHz I SM Industrial, Scientific and 5150-5350 MHz coverage of larger distances. The association of Multiple Medical Input Multiple Outputs (MIMO) systems (which e xplo it 5725-5825 MHz UWB Ultra Wide Band 3100 -10600 MHz * Corresponding author: Wide Band (UWB) antenna. One defin ition requires a er.rakeshy adav [email protected] (Rakesh Kumar Yad av) Published online at http://journal.sapub.org/jwnc UWB antenna to have a fractional BW greater than 0.25 [1]. Copyright © 2012 Scientific & Academic Publishing. All Rights Reserved An alternate and more recent definition places the limit at 0.2 118 Rakesh Kumar Yadav et al.: Parametric Study of UWB Biconical Antenna for Wide-band Applications [2]. That is given by equation 1: severe if the thick dipole takes the shape of a biconical 0.25 antenna. The biconical antenna evolved towards a single = 2 (1) + ℎ − 0.20 cone which presents a limited well matched impedance Where is the upper end frequency and is lower end ℎ ≥ � bandwidth but a stable phase centre within the bandwidth. frequency of the antenna operational band. Another evolution of the biconical antenna is the bow-t ie ℎ There are three classes of UWB antennas based on their antenna, the flat version of the biconical antenna. applications. Several techniques have also been proposed to improve a. First is the "DC- to- Daylight" class having the maximal the antenna bandwidth, for example, the use of a bevelling bandwidth. plate, a double feed or an asymmetrical feed arrangement, a b. Second is the "multinarrow band" class- receiving or trident-shaped feeding strip etc. However, they are not planar detecting narrowband signals across broad swaths of structures because their ground planes are perpendicular to frequencies. the radiators. This drawback limits their practical c. Third the "modern" UWB antennas- having 3: 1 applications due to their large area. bandwidth. A modern UWB antenna must be well Biconical antenna was first introduced by Schelkunoff [7]. behaved and consistent across the operation bandwidth of In theory, both the input impedance and radiation pattern of antenna [3]. infinite biconical antenna have nothing to do with the frequency characteristics, As regards to finite biconical antenna, both the input impedance and radiation pattern 2. Biconical Antenna change as the frequency changes. A biconical antenna is used A biconical antenna consists of an arrangement of two in a system that requires 360 degree coverage in the conical conductors, which is driven by potential, charge, or azimuthal plane with a particular coverage in the elevation an alternating magnetic field at the vertex. The conductors plane [8]. Due to the frequency independent nature of its have a common axis and vertex. The two cones face in construction, the biconical antenna is well-suited for use in opposite directions. Biconical antennas are broadband dipole ultra – wide band systems. The biconical antenna, consisting antennas, typically exhibiting a bandwidth of 3 octaves or of two linear cones, excited symmetrically at the apices [9]. more . In Year 2003, J. D. Morrow proposed a biconical antenna Further, when the wireless systems that are potential which covers the frequency range of 3.1 GHz to 10.6 GHz candidates for cognitive radio are considered, UWB seems to [10]. Latter D.N. Black, Jr. and T.A. Brunasso developed a be one of the tempting choices because it has an inherent high impedance bicone antenna covering 25 MHz to 6 GHz potential to fulfil some of the key requirements of cognitive [11]. However in 2009, Z. Hou, W. Li, W. Jian and Ma radio. These requirements include no spurious interference Laixuan proposed a new bicone antenna for EM C test to licensed systems, adjustable pulse shape, bandwidth, application, which found to be suitable in frequency range of trans mitted power, support of various throughputs, provision 500 MHz to 2.5 GHz, and I. Gronich developed a bicone of adaptive multiple access, and security of information. antenna with asymmetric cones covering the frequency band However, it is not claimed that a cognitive wireless system of 2 GHz to 18 GHz [12, 13]. In 2010, Y. Huichun and G. using only the UWB technology can handle all the Yougang developed an anti-interference bicone antenna requirements of an ideal cognitive radio. Advances in useful for wireless communication application in the reconfigurability of RF front-ends, particularly frequency range of 0.85 GHz to 2.5 GHz [14]. Recently, S. reconfigurable antennas, afford a new “hardware” dimension Zahirah Sapuan, A. Kazemipour, M. Zarar and M. Jenu for optimizing the performance of wireless communication developed a bicone antenna suitable to be used as calibration systems. Recent development in communication, antenna in the frequency band of 200 MHz to 2 GHz [15]. surveillance and Electronics Support Measurer (ESM) Biconical (or "Bicon") antenna is a broadband radiator, demands antennas with very wide bandwidth and omni however its poor efficiency at low frequencies, results in low radiation pattern. Broadband antenna has received much field strengths when compared to the input power. It may attention for application in wireless communication systems, behave either an omnidirectional or directional antenna if it listed in Table 1. Several Antennas have already been is kept vertical or horizontal respectively. reported [4], to suit the above mentioned requirement. The impedance of the feeding point of biconical antenna is Among these antennas, one of the most useful usually chosen to be 50 Ω, however when the vertical angle omnidirectional antennas is the biconical horn [5]-[6]. of the conical geometry is enlarged, impedance becomes Antenna engineers discovered that, starting from a dipole small. And it becomes a dipole aerial if vertical angle or monopole antenna, thickening the arms results in an reduces it to the utmost limit, and the impedance range is increased bandwidth. Thus, for a thick dipole or monopole found to be about 73Ω to 50Ω. Hence the Biconical antennas antenna, the current distribution is no longer sinusoidal and are often used in electromagnetic interference (EMI) testing where this phenomenon hardly affects the radiation pattern either for immunity testing, or emissions testing from 25-200 of the antenna, therefore this strongly influences the input MHz (Commercial specifications) or 30-200 MHz (Military impedance too.